The present invention relates to a plate device for withdrawing and moving a molding of thermoformed objects or articles away from a single station thermoforming apparatus or press acting on a sheet or tape of thermoplastic material.
Sucking and non-sucking plate devices provided with engaging means for the objects have already been proposed and widely used in the art. Such devices are prevailingly formed of a support arm which supports cantileverwise a withdrawing plate at one end thereof, and an actuation means arranged to move along a straight path the arm and thus the plate in a lateral direction with respect to the press between a withdrawing position in the press between a female mold or die and a counterdie in their open condition, i. e. spaced apart from one another, and a position away from the press.
However, first of all in consideration of the trend of increasing the number of thermoforming cycles in time unit in order to minimise the production costs, the risk exists of generating substantial inertia forces due to high accelerations and decelerations being produced in each working cycle.
Secondly, the withdrawing plates used up to now in the single-station thermoforming presses are all provided with a bracket with no guiding means along its sides or on its front opposite the front side of the plate at the mold or die zone.
A withdrawing plate of this type obviously has limitations in use owing to unavoidable vibrations given to the plate in relation to the production cycles and dimensions and weight of the same.
The important novelty of the present invention is that of having eliminated the difficulties preventing plate guide systems acting between the male and female dies mounted on the thermoforming press from being adopted.
Such obstacles were due to the structure of any thermoforming press, the presence of the sheet transport means inserted therein and possible guide means for the dies.
Accordingly, the main object of the present invention is to provide a plate device for withdrawing and carrying away a molding of thermoformed objects from a thermoforming single-station apparatus or press arranged to make it possible to carry out a safe and regular withdrawing of all the objects from a die with no variations in the configuration and geometry of mutual positioning of the objects.
Another object of the present invention is that such a plate device can be adapted to any types of thermoforming single-station press with female die arranged either below or above a counterdie or male die.
These and still other objects which will better appear below are attained by a plate device for withdrawing and carrying away a molding of thermoformed objects from a thermoforming single-station apparatus or press having a support frame, a feeder of sheet or tape material as well as a female die and a counterdie which are movably arranged one with respect to the other between a closed position in which the sheet or tape material fed by the feeder is thermoformed, and an opened position in which the female die and the counterdie are mutually spaced apart one with respect to the other, the said plate device comprising actuation means designed to move it along a straight path between a withdrawing position of the objects from the female die, while the latter is in its opened position, and an object releasing position away from the die, and being characterised in that it comprises guide means in the press arranged to engage and guide it at least along a length of the straight path thereof between the withdrawing and the releasing positions, thereby preventing vibrations from being. imparted to the plate during or immediately after withdrawal of the objects.
Advantageously, the said guide means can be arranged on a component of the press or on the feeder of the sheet or tape material or on the die.